> Word of mouth works, but can be very slow

Is slow growth not fine? I think organic growth is healthier for society. All this explosive never ending economic growth we see today seems pathological to me.

> Where did the first person in the chain hear about it if not for marketing or self promotion?

Those first users are presumed to be close to the person who made the product. People trust their friends. They'll tell other people about it if they liked it.

> my reverse image search service SauceNAO

Thank you for making SauceNAO. I first saw it on image boards, it's a well-integrated feature of those sites.

I'm not sure if you have a business model so I can't tell if advertising would present conflicts of interest.